Pneumatic elevators



July 6, 1965 B. w. CRAIG PNEUMATIC ELEVATORS Filed Aug. 16, 1963 United States Patent 3,193,331 PNEUMATIC ELEVATORS Brian W. Craig, Withington, Manchester, England, as-

signor to Henry Simon Limited, Stockport, England, a British company Filed Aug. 16, 1963, Ser. No. 302,563 Claims priority, application Great Britain, Aug. 20, 1962, 31,833/62 4 Claims. (Cl. 302-32) This invention relates to suction-operated pneumatic elevators and is particularly directed to elevators having intake nozzles mounted in mixed communication with hoppers or the like from which material is delivered to an elevating duct.

Where a single substantially vertical elevating duct having a relatively fixed intake nozzle serves to transport all materials discharged from an outlet port at the lowest extremity of a collecting means such as a hopper, bin, or trough (hereinafter referred to as a hopper), and where the said intake nozzle is connected with the bottom of the said elevating duct by a connecting duct arranged to direct the material from the nozzle into the elevating duct, it is a disadvantage that if a choke occurs or the elevator is stalled, as for example by a failure of the source of suction, so that entrained material in the elevating duct is precipitated into the connecting duct and lower portion of the elevating duct, the operation of effecting a clearance of the precipitated material may necessitate the opening or dismantling of the connecting duct and consequent spillage of material into the space outside the hopper.

The object of this invention is to overcome this disadvantage.

According to the invention, a suction-operated pneumatic elevator for transporting material from a collecting hopper comprises a substantially vertical elevating duct, to the outlet end of which suction is to be applied and which at its lower end is in communication with the interior of the collecting hopper, characterised in that an outlet port at the base of the hopper communicates with the interior of a trough-like elevator-boot member which is in sealing engagement with the lower extremities of the hopper walls and with the lower extremities of a connecting duct leading to the elevating duct, and into which boot member material is drawn downwardly from the hopper by a flow of air into the said connecting duct, which connecting duct is formed on the outside of one wall of the hopper in such a way that a part of the said wall of the hopper forms a common party wall element between the hopper and the connecting duct, the said common party Wall element or part thereof being detachably mounted so that it can be removed to enable trapped material to be released into the hopper.

The trough-like elevator-boot member may be extended in a direction away from the connecting duct so as to communicate with an air inlet duct through which a controlled amount of scavenging air can be passed to the foot of the connecting duct to assist in the elevation of material fed thereto from the hopper.

Preferably the detachably mounted party Wall element may be supported on a footstep element and rest on a resilient element of the hopper wall, into sealing engagement with which it is drawn by suction during normal operation but from which it can be disengaged by precipitated material if the source of suction fails.

The detachably mounted party wall element may be provided with an adjustable extension of its lower extremity whereby the air-flow conditions in the trough-like elevator-boot member may be adjusted.

A suction-operated pneumatic elevator according to this invention may be provided at a convenient position above the junction to the connecting duct, with an automatically self-closing air inlet port in the form of an adaptor to which a flexible suction pipe can be coupled for the purpose of removing by suction material which is released from the connecting duct into the hopper when the common party wall element is detached from its seatmg.

An embodiment of the invention will now be described, with reference, by way of example to the accompanying drawings, in which:

FIGURE 1 is a front perspective view of a double hopper arrangement in accordance with the invention, and

FIGURE 2 is a rear perspective view of the arrangement shown in FIGURE 1.

The arrangement shown comprises a vertical elevating duct 1 which serves to transport all material from two associated hoppers 2. Each hopper is provided with a trough-like elevator-boot member 4 and connecting duct 5, the two ducts 5 being parallel to convergent edges 6 and coming to an inverted Y-junction with duct 1. A part of the rear wall of each hopper 2 forms a common party wall with its connecting duct 5 and a part 7 of this wall is removable, it being drawn by suction, during normal operation, against resilient sealing strip 8.

In use, the material to be transported from the hoppers 2 is entrained in air flowing into the connecting ducts 5 from whence the entrained material passes into the vertical elevating duct 1. If the speed of the air flow through, say, one of the ducts 5 is substantially reduced, or if the air flow is arrested, then the entrained material falls back into the corresponding boot member 4 until the opening at the bottom of the duct 5 is choked and thereafter the material tends to build up in the duct 5. As, however, the wall part 7 is no longer held in position against the sealing strips 8 due to suction failure, the wall part 7 falls into the hopper 2 as does the accumulated choke" material so that outside scattering and/or contamination of the material is avoided.

To restore the pneumatic system operational conditions after such precipitation of material, it is first necessary to remove from the boot member 4 and the part of the hopper above it such choke material as impedes the flow of air into the bottom of the connecting duct 5 so that the correct conditions for material entrainment can be achieved. This clearance of material can be performed manually by dragging the choke material into available space within the hopper 2 until it is possible to replace the wall part 7 on the sealing strips 8. It will be appreciated that it is necessary to replace part 7 as otherwise the velocity of the air entering the open front of the connecting duct 5 will be insuflicient to entrain the material. When a sufiicient quantity of air is flowing into the connecting duct 5 material can be fed into the boot member 4 until the excess of choke material in the hopper 2 has been entrained and elevated. in the performance of this operation additional scavenging air may be admitted to the boot member 4 through an air inlet arrangement comprising a duct 9 with flared end it) and a control valve 11.

It will however be appreciated that the feeding of the excess choke material in the hopper 2 to the boot member 4 requires considerable care because a rush of material from the hopper 2 will tend to choke the inlet to the connecting duct 5 and cause a further precipitation of the material in transit in the elevating duct 1. To simplify the restoration of operational conditions, there is pro vided, at a point as high up the elevating duct 1 as the shape of the associated machinery permits, an automatically closable inlet 1?. to the duct 1 to which inlet 12 a flexible hose 13 can be attached so that air can flow into the otherwise choked elevating duct 1, the flexible hose 13 thus becoming a movable suction device which can be used in the manner of a vacuum cleaner nozzle for re- 3 moving excess choke material from the hopper 2. The suction hose device 13 is first used to clear away sufiicient material to enable the wall part 7 to be replaced, and thereafter its use is continued until the clearing away of excess choke material from the entrainment position permits the pneumatic elevator system to function normally.

What I claim is:

1. A suction-operated pneumatic elevator for transporting material from a collecting hopper comprising a substantially vertical elevating duct in communication at its lower end with the interior of the collecting hopper, means for applying suction to the outlet end of the elevating duct, a trough-like elevator boot member, whereof the interior communicates with the base of the hopper, and which is in sealing engagement with the lower extremities of the hopper walls, and a connecting duct leading to the elevating duct and in sealing engagement at its lower extremities with the boot member and into which boot member material is drawn downwardly from the hopper by a flow of air into the connecting duct, the connecting duct being formed on the outside of one wall of the hopper so that a part of the wall of the hopper forms a common party wall element between the hopper and the connecting duct, the common party wall element or part thereof being held in position by suction in the elevating duct so that it is automatically removed to release precipitated trapped material into the hopper on failure of suction.

2. An elevator as claimed in claim 1, comprising'resil- V ient means secured to the hopper wall and against which the common party wall element rests and is drawn into sealing engagement with said resilient means by suction during normal operation'of the elevator.

3. An elevator as claimed in claim 1 wherein the boot member is extended in a direction away from the connecting duct to communicate with an air inlet duct through which a controlled amount of scavenging air can be passed to the foot of the connecting duct to assist in the elevation of material fed thereto from the hopper.

4. An elevator as claimed in claim 1 comprising a closable air inlet port provided on the vertical elevating duct, which inlet port is in the form of an adaptor to which a flexible suction hose can be coupled for the purpose of removing by suction, material which is released from the connecting duct into the hopper when the common party wall element is detached from its seating.

References Cited'by the Examiner UNITED STATES PATENTS 636,372 11/99 Williamson 30232 2,689,688 9/54 Ball 302--32 FOREIGN PATENTS 920,039 3/63 Great Britain.

SAMUEL F. COLEMAN, Primary Examiner. ANDRES H. NIELSEN, Examiner. 

1. A SUCTION-OPERATED PNEUMATIC ELEVATOR FOR TRANSPORTING MATERIAL FROM A COLLECTING HOPPER COMPRISING A SUBSTANTIALLY VERTICAL ELEVATING DUCT IN COMMUNICATION AT ITS LOWER END WITH THE INTERIOR OF THE COLLECTING HOPPER, MEANS FOR APPLYING SUCTION TO THE OUTLET END OF THE ELEVATING DUCT, A TROUGH-LIKE ELEVATOR BOOT MEMBER, WHEREBY THE INTERIOR COMMUNICATES WITH THE BASE OF THE HOPPER, AND WHICH IS IN SEALING ENGAGEMENT WITH THE LOWER EXTREMITIES OF THE HOOPER WALLS, AND A CONNECTING DUCT LEADING TO THE ELEVATING DUCT AND IN SEALING ENGAGEMENT AT ITS LOWER EXTREMITIES WITH THE BOOT MEMBER AND INTO WHICH BOOT MEMBER MATERIAL IS DRAWN DOWNWARDLY FROM THE HOPPER BY A FLOW OF AIR INTO THE CONNECTING DUCT, THE CONNECTING DUCT BEING FORMED ON THE OUTSIDE OF ONE WALL OF THE HOPPER SO THAT A PART OF THE WALL OF THE HOPPER FORMS A COMMON PARTY WALL ELEMENT BETWEEN THE HOPPER AND THE CONNECTING DUCT, THE COMMON PART WILL ELEMENT OR PART THEREOF BEING HELD IN POSITION BY SUCTION IN THE ELEVATING DUCT SO THAT IT IS AUTOMATICALLY REMOVED TO RELEASE PRECIPITATED TRAPPED MATERIAL INTO THE HOPPER ON FAILURE OF SUCTION. 